Valve-gear



(No Model.) y Y W. J. LEWIS.

VALVE GEAR. No. 535,545. Patented Mar. '12,1895'.

se a Namen WALLACE J. LEWIS, OF ST. LOUIS, MISSOURI, ASSIGNOR TO THELEWIS VALVE GEAR COMPANY, OF EAST ST. LOUIS, ILLINOIS.

VALVE-G EAR.

SPECIFICATION forming part of Letters Patent No. 535,545faateaMa1-ch 12,1895.

Application tiled March 8. 1892.

.To all whom it may concern.:

Be it known that I, WALLACE J. LEWIS, residing at the city of St. Louis,Stateof Missouri, have invented certain new and useful Improvements inValve-Gear; and I hereby declare the following to be a full, clear, andexact description of the same, reference being had to the accompanyingdrawings, in which- Figure 1 is an elevation of a valve gear embodyingmy invention, the side frame which supports the gear being omitted, thefull lines indicating the connections preferred when the throw of thevalve is effected by the piston of the opposite side, and the dottedlines to the left of the drawing indicating the preferred connectionswhen the throw of the valves is effected by an eccentric on the drivingaxle, and Fig. 2, is a plan View of the parts shown in full line Fig. 1,a portion of the supporting frame being shown.

Like symbols refer to like parts wherever they occur.

My invention relates to the construction of that class of valve gearwherein the movements to overcome the lap and lead of the valve, and thethrow of the valve are eected by different forces,-as for instance, thetwo opposite pistons, or cross-heads, where two engines are employed asin the case of locomotives, marine engines, &c. For purposes ofillustration I have shown the novel combinations connected so as toobtain the movement to overcome the lap and lead from one side and thethrow from the opposite side, and through the medium of rock-shafts (asin the patent of Matton, No. 285,286, and my own patents, Nos. 331,799and 355,770); but do not intend the same as a matter of limitation, forsaid movements may also he obtained'from eccentrics on a driving axle orits equivalent;- and further, the novel combination which embraces theunit of construction may be used with a single engine. I have thereforeadded to Fig. 1, dotted lines which taken in connection with thedescription will clearly indicate to any one skilled in the art, how myinvention may be applied to single engines as well as double engines,and how the power to move the valves may be applied by eccentrics as 5owell as cross-heads or rock-shafts.

The function of the valve being to regulate Serial No. l124 ,158. (Nomodel.)

the alternate admission and discharge of steam at each end of thecylinder, the valve is accordingly set so as to be at a point beyond themiddle of its travel-the required lap and lead-when the piston is at thebeginning of its stroke, and in coming to said position the valveovercomes the lap and lead so that the admission of steam may fill theclearance space at the beginning of the stroke of the piston.

The travel of a slide-valve operated by the ordinary link motion isslightly greater during its passage over the middle portion of itsstroke than it is at the outer portions thereof.

In order to work effectively and economically either with full boilerpressure or expansivel y, it is desirable that the middle portion of thevalve travel should be accelerated and the remainder of its travelcorrespondingly retarded, and the longer the retarded movement can bemaintained consistent with the next following rapid movement, the betterwill be the results.

To accelerate the middle portion of the travel of the valve and retardthe remainder of its travel, I interpose between the valve and its twosources of movement a fioating lever with which said powers areconnected, and in order to reverse the engines I provide a movableslide-box and a slide in said box connecting the slide-box with thereversing lever, and interposing the slide between the floating leverand one of said sources of movement, whereby engines having valve-gearof the general character specied may be readily reversed with theexercise of much less power than is now required-and the slide valvesmay be held atany desired point of cut-off.

There are other, minor, features of invention, all as will hereinaftermore fully appear.

I will now proceed to describe my invention more fully so that othersskilled in the art to which it appertains may apply the same.

In the drawings, which show the unit of organization or the combinationas applicable to a single engine, and which is to be doubled for alocomotive or double engine--A indicates a portion of one side of theframe, and B the cross-head of the piston. Connecting IOO saidcross-head B, or its equivalent with' the stem S of the slide valve ofsaid side, is a floating lever 1, which imparts to said valve itsmovement to overcome the lap and lead; and connecting said floatinglever with the arm 3, of a long rock-shaft 4, is a link 2, whereby thethrow of the valve on the opposite side is effected.

5, indicates a second long rock-shaft which extends transversely ot' thelocomotive frame and at its distant end is connected with the oatinglever (l) ofthe opposite engine. Said long rock-shaft 5, is providedwith a crank arm 6, through which it is connected by a link 7, with onearm 8 of a short rock-shatt 9, journaled in the frame A, the other arm10, of said short rock-shaft being connected by a link 1l, with a slide12, adapted to move in a pivoted guide-box 13, the opposite end of saidslide 12, being connected to the floating lever 1, by a terminal link14, as indicated in dotted lines, Fig. 1. As the shaft 5, has itsdistant end connected with the floating lever and cross-head of theopposite side, it will be apparent that through the medium of thedevices 5 to 14, just described, the throw of valve stem S will beeffected from the piston of the opposite side. In case however, it isdesired to apply the power to the floating lever by means of eccentricsinstead ot' rocksnafts, or to use the devices in conjunction with asingle engine, the links 2 and 7, and the long rock-shafts 4 and 5, maybe omitted, and an eccentric (5a) and link (7a) as indicated in dottedlines on the left of Fig. 1, may be employed to impart the throw t0 thevalve gear mechanism, the floating lever l, receiving its movement toovercome the lap and lead either from the cross-head B, as shown,

or from a second eccentric and link connection similar to that shown indotted lines.

In order to obtain a simpler and efficient reversing mechanism, and onewhich will distribute the friction over a larger surface and reduce thepower required to operate it, I arrange the slide 12 in a guide-box 13,movably supported as at 16, on a bracket 17-17, secured to pillars a, a,projecting from the frame A. The pivot 16 should be at such a point onthe line between the center of the short rock-shaft 9 and the point ofattachment of terminal link 14 to floating lever 1, relative to therespective lengths of the slide bar and the terminal link, as Willimpart the required travel to the lever 1, equal distances fromiitscentral position. It is important that the point of attachment (F) ofthe terminal link to the floating lever should be confined by suitableguides to move in a straight line. In the present device, this action issecured by constructing a cross-head on the floating lever at the Fpoint, the ends of the crosshead having recesses, which confine it toprojecting bars on the brackets 17 and 17a.

kIntegral with or connected to the guide box 13, is a pend ent arm 15,by which the rotation of the movable slide box 13 may be effected,

and said arm'is connected by a link fr with a rock-beam R, pivoted as atr2, and thence by an intermediate link r to the reversing lever R.

lVhen through the medium of the reversing lever and arm 15, or theirequivalents, the pivoted guide-box 13 is moved into its extremeposition, either above or below, the valve will be caused to work atfull cut-off, and at intermediate positions a graduated travel andcutott 'will be obtained, while when the slide bar is in the planepassing through the point of attachment of link 14, to floating lever 1,and through the center of short rocker-shaft 9, the travel of the valvewill be limited to its lap and lead.

If the rocker arm 10, is above the line and the. slide bar is alsoraised the floating lever 1, will be caused to move backward, and if thearm 10, is below the line and the slide bar raised abo-ve the line, thefloating lever 1, will be caused to move forward.

The operation of the valve gearing hereinbefore described will be asfollows: From the cross-head B, or equivalent source, the power whichcontrols the movement to overcome the lap and lead of the valve isapplied to the floating lever 1, at 1?, the connection ofthe terminallink 14 with the floating lever as at F, acting for the time being asthe fulcrum, so that the lever may be said to be for the time 'being alever ofthe first order. Next the power which controls the throw ot' thevalve is applied to the floating lever at the points F, and P in turnbecomes the fulcrum, and the lever one of the third order; but as thesetwo movements, whether the same be derived from eccentrics (5*, tbc.) orfrom the cross-head B- of opposite sides-do not synchronize, theircourses 'are at one moment-in the same direction, and a moment later inopposite directions. When, therefore, the points P and F of theVfloating lever 1, are moving in the same direction, the slide-valvemoves less rapidly or is retarded in its movement, and when the points Pand F are moving in opposite directions, the movement of the slide valveis accelerated, with the results and advantages hereinb'efore pointedout.

Having thus described the nature and operation of my invention, whatIclaim, and desire to secure by Letters Paten-t, is-

l. In a valve gear the combination witha floating valve-lever, operatedat two separate points by independent movements respectively from eachengine of a double engine, whereby an accelerated or retarded motion canbe give-'n to the valve, of a reversing lever provided with a slide-box,and a slide in said box connected to said valve-lever by which one ofsaid movements is communicated, whereby the double engine can bereversed and the slide valves thereof held at any point of cutoffdesired, substantially as and for the purposes specified.

2. In a valve gear mechanism, the combination with thevalve of afloating lever, connections for actuating the same, the whole ar- ICOIIO

ro 12 and link 14, which connects the slide and floating lever, apivoted guide box for the slide, and a rock-shaft which actuates theslide; substantially as and for the purposes specified.

In testimony whereof I affix my signature, l 5 in presence of twoWitnesses, this 5th day of March, 1892.

WALLACE J. LEWIS.

Witnesses:

D. MCARTHUR, L. B. FISH.

